#include<iostream>
using namespace std;

int fib(int a);


void main(void)
{
	int a;
	int ans;

	cout << "input num" << endl;
	cin >> a;

	ans = fib(a);
	cout << "answer" << ans;
}

int fib(int a)
{
	if (a < 3)
		return 1;
	else
		return fib(a - 1) + fib(a - 2);
}